/**
 * tiny_jpeg.h
 *
 * Tiny JPEG Encoder
 *  - Sergio Gonzalez
 *
 * This is a readable and simple single-header JPEG encoder.
 *
 * Features
 *  - Implements Baseline DCT JPEG compression.
 *  - No dynamic allocations.
 *
 * This library is coded in the spirit of the stb libraries and mostly follows
 * the stb guidelines.
 *
 * It is written in C99. And depends on the C standard library.
 * Works with C++11
 *
 *
 * ==== Thanks ====
 *
 *  AssociationSirius (Bug reports)
 *  Bernard van Gastel (Thread-safe defaults, BSD compilation)
 *
 *
 * ==== License ====
 *
 * This software is in the public domain. Where that dedication is not
 * recognized, you are granted a perpetual, irrevocable license to copy and
 * modify this file as you see fit.
 *
 */

// ============================================================
// Usage
// ============================================================
// Include "tiny_jpeg.h" to and use the public interface defined below.
//
// You *must* do:
//
//      #define TJE_IMPLEMENTATION
//      #include "tiny_jpeg.h"
//
// in exactly one of your C files to actually compile the implementation.


// Here is an example program that loads a bmp with stb_image and writes it
// with Tiny JPEG

/*

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"


#define TJE_IMPLEMENTATION
#include "tiny_jpeg.h"


int main()
{
    int width, height, num_components;
    unsigned char* data = stbi_load("in.bmp", &width, &height, &num_components, 0);
    if ( !data ) {
        puts("Could not find file");
        return EXIT_FAILURE;
    }

    if ( !tje_encode_to_file("out.jpg", width, height, num_components, data) ) {
        fprintf(stderr, "Could not write JPEG\n");
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}

*/


#include "tiny_jpeg.h"

#define TJE_IMPLEMENTATION


#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"  // We use {0}, which will zero-out the struct.
#pragma GCC diagnostic ignored "-Wmissing-braces"
#pragma GCC diagnostic ignored "-Wpadded"
#endif

#define LOGW(fmt, ...) do {;} while(0)

// ============================================================
// Internal
// ============================================================
#ifdef TJE_IMPLEMENTATION

#define OPTIMIZE_ATTR //__attribute__((optimize("O2")))

#define tjei_min(a, b) ((a) < b) ? (a) : (b);
#define tjei_max(a, b) ((a) < b) ? (b) : (a);






#if defined(_MSC_VER)
#define TJEI_FORCE_INLINE __forceinline
// #define TJEI_FORCE_INLINE __declspec(noinline)  // For profiling
#else
#define TJEI_FORCE_INLINE static // TODO: equivalent for gcc & clang
#endif

// Only use zero for debugging and/or inspection.
#define TJE_USE_FAST_DCT 1



#define TJEI_BUFFER_SIZE 1024

#ifdef _WIN32

#include <windows.h>
#ifndef snprintf
#define snprintf sprintf_s
#endif
// Not quite the same but it works for us. If I am not mistaken, it differs
// only in the return value.

#endif

#ifndef NDEBUG



#define tje_log(fmt,...) do {;} while(0)


#else  // NDEBUG
#define tje_log(msg)
#endif  // NDEBUG





typedef struct {
    void*           context;
    tje_write_func* func;
} TJEWriteContext;

typedef struct {
    uint8_t huffsize[4][257];
    uint16_t huffcode[4][256];
    // Huffman data.
    uint8_t         ehuffsize[4][257];
    uint16_t        ehuffcode[4][256];
    uint8_t const * ht_bits[4];
    uint8_t const * ht_vals[4];

    // Cuantization tables.
    uint8_t         qt_luma[64];
    uint8_t         qt_chroma[64];

    // fwrite by default. User-defined when using tje_encode_with_func.
    TJEWriteContext write_context;

    // Buffered output. Big performance win when using the usual stdlib implementations.
    size_t          output_buffer_count;
    uint8_t         output_buffer[TJEI_BUFFER_SIZE];
} TJEState;

// ============================================================
// Table definitions.
//
// The spec defines tjei_default reasonably good quantization matrices and huffman
// specification tables.
//
//
// Instead of hard-coding the final huffman table, we only hard-code the table
// spec suggested by the specification, and then derive the full table from
// there.  This is only for didactic purposes but it might be useful if there
// ever is the case that we need to swap huffman tables from various sources.
// ============================================================


// K.1 - suggested luminance QT
static const uint8_t tjei_default_qt_luma_from_spec[] = {
    16, 11, 10, 16, 24, 40, 51, 61,
    12, 12, 14, 19, 26, 58, 60, 55,
    14, 13, 16, 24, 40, 57, 69, 56,
    14, 17, 22, 29, 51, 87, 80, 62,
    18, 22, 37, 56, 68, 109, 103, 77,
    24, 35, 55, 64, 81, 104, 113, 92,
    49, 64, 78, 87, 103, 121, 120, 101,
    72, 92, 95, 98, 112, 100, 103, 99,
};

// Unused
#if 0
static const uint8_t tjei_default_qt_chroma_from_spec[] = {
    // K.1 - suggested chrominance QT
    17, 18, 24, 47, 99, 99, 99, 99,
    18, 21, 26, 66, 99, 99, 99, 99,
    24, 26, 56, 99, 99, 99, 99, 99,
    47, 66, 99, 99, 99, 99, 99, 99,
    99, 99, 99, 99, 99, 99, 99, 99,
    99, 99, 99, 99, 99, 99, 99, 99,
    99, 99, 99, 99, 99, 99, 99, 99,
    99, 99, 99, 99, 99, 99, 99, 99,
};
#endif

static const uint8_t tjei_default_qt_chroma_from_paper[] = {
    // Example QT from JPEG paper
    16,  12, 14,  14, 18, 24,  49,  72,
    11,  10, 16,  24, 40, 51,  61,  12,
    13,  17, 22,  35, 64, 92,  14,  16,
    22,  37, 55,  78, 95, 19,  24,  29,
    56,  64, 87,  98, 26, 40,  51,  68,
    81, 103, 112, 58, 57, 87,  109, 104,
    121, 100, 60,  69, 80, 103, 113, 120,
    103, 55, 56,  62, 77, 92,  101, 99,
};

// == Procedure to 'deflate' the huffman tree: JPEG spec, C.2

// Number of 16 bit values for every code length. (K.3.3.1)
static const uint8_t tjei_default_ht_luma_dc_len[16] = {
    0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0
};
// values
static const uint8_t tjei_default_ht_luma_dc[12] = {
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};

// Number of 16 bit values for every code length. (K.3.3.1)
static const uint8_t tjei_default_ht_chroma_dc_len[16] = {
    0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0
};
// values
static const uint8_t tjei_default_ht_chroma_dc[12] = {
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};

// Same as above, but AC coefficients.
static const uint8_t tjei_default_ht_luma_ac_len[16] = {
    0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d
};
static const uint8_t tjei_default_ht_luma_ac[] = {
    0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
    0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08, 0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0,
    0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28,
    0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
    0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
    0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
    0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,
    0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5,
    0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2,
    0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
    0xF9, 0xFA
};

static const uint8_t tjei_default_ht_chroma_ac_len[16] = {
    0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77
};
static const uint8_t tjei_default_ht_chroma_ac[] = {
    0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
    0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0,
    0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34, 0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26,
    0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
    0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
    0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
    0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,
    0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,
    0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,
    0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
    0xF9, 0xFA
};


// ============================================================
// Code
// ============================================================

// Zig-zag order:
static const uint8_t tjei_zig_zag[64] = {
    0,   1,  5,  6, 14, 15, 27, 28,
    2,   4,  7, 13, 16, 26, 29, 42,
    3,   8, 12, 17, 25, 30, 41, 43,
    9,  11, 18, 24, 31, 40, 44, 53,
    10, 19, 23, 32, 39, 45, 52, 54,
    20, 22, 33, 38, 46, 51, 55, 60,
    21, 34, 37, 47, 50, 56, 59, 61,
    35, 36, 48, 49, 57, 58, 62, 63,
};

// Memory order as big endian. 0xhilo -> 0xlohi which looks as 0xhilo in memory.
static uint16_t tjei_be_word(const uint16_t le_word)
{
    uint16_t lo = (le_word & 0x00ff);
    uint16_t hi = ((le_word & 0xff00) >> 8);
    return (uint16_t)((lo << 8) | hi);
}

// ============================================================
// The following structs exist only for code clarity, debugability, and
// readability. They are used when writing to disk, but it is useful to have
// 1-packed-structs to document how the format works, and to inspect memory
// while developing.
// ============================================================

static const uint8_t tjeik_jfif_id[] = "JFIF";
static const uint8_t tjeik_com_str[] = "Created by Tiny JPEG Encoder";

// TODO: Get rid of packed structs!
#pragma pack(push)
#pragma pack(1)
typedef struct {
    uint16_t SOI;
    // JFIF header.
    uint16_t APP0;
    uint16_t jfif_len;
    uint8_t  jfif_id[5];
    uint16_t version;
    uint8_t  units;
    uint16_t x_density;
    uint16_t y_density;
    uint8_t  x_thumb;
    uint8_t  y_thumb;
} TJEJPEGHeader;

typedef struct {
    uint16_t com;
    uint16_t com_len;
    char     com_str[sizeof(tjeik_com_str) - 1];
} TJEJPEGComment;

// Helper struct for TJEFrameHeader (below).
typedef struct {
    uint8_t  component_id;
    uint8_t  sampling_factors;    // most significant 4 bits: horizontal. 4 LSB: vertical (A.1.1)
    uint8_t  qt;                  // Quantization table selector.
} TJEComponentSpec;

typedef struct {
    uint16_t         SOF;
    uint16_t         len;                   // 8 + 3 * frame.num_components
    uint8_t          precision;             // Sample precision (bits per sample).
    uint16_t         height;
    uint16_t         width;
    uint8_t          num_components;        // For this implementation, will be equal to 3.
    TJEComponentSpec component_spec[3];
} TJEFrameHeader;

typedef struct {
    uint8_t component_id;                 // Just as with TJEComponentSpec
    uint8_t dc_ac;                        // (dc|ac)
} TJEFrameComponentSpec;

typedef struct {
    uint16_t              SOS;
    uint16_t              len;
    uint8_t               num_components;  // 3.
    TJEFrameComponentSpec component_spec[3];
    uint8_t               first;  // 0
    uint8_t               last;  // 63
    uint8_t               ah_al;  // o
} TJEScanHeader;
#pragma pack(pop)


static void tjei_write(TJEState* state, const void* data, size_t num_bytes, size_t num_elements)
{
    size_t to_write = num_bytes * num_elements;

    // Cap to the buffer available size and copy memory.
    size_t capped_count = tjei_min(to_write, TJEI_BUFFER_SIZE - 1 - state->output_buffer_count);

    memcpy(state->output_buffer + state->output_buffer_count, data, capped_count);
    state->output_buffer_count += capped_count;

    assert(state->output_buffer_count <= TJEI_BUFFER_SIZE - 1);

    // Flush the buffer.
    if(state->output_buffer_count == TJEI_BUFFER_SIZE - 1) {
        state->write_context.func(state->write_context.context, state->output_buffer, (int)state->output_buffer_count);
        state->output_buffer_count = 0;
    }

    // Recursively calling ourselves with the rest of the buffer.
    if(capped_count < to_write) {
        tjei_write(state, (uint8_t*)data + capped_count, to_write - capped_count, 1);
    }
}

static void tjei_write_DQT(TJEState* state, const uint8_t* matrix, uint8_t id)
{
    uint16_t DQT = tjei_be_word(0xffdb);
    uint16_t len ;
    uint8_t precision_and_id;
    tjei_write(state, &DQT, sizeof(uint16_t), 1);
    len = tjei_be_word(0x0043); // 2(len) + 1(id) + 64(matrix) = 67 = 0x43
    tjei_write(state, &len, sizeof(uint16_t), 1);
    assert(id < 4);
    precision_and_id = id;  // 0x0000 8 bits | 0x00id
    tjei_write(state, &precision_and_id, sizeof(uint8_t), 1);
    // Write matrix
    tjei_write(state, matrix, 64 * sizeof(uint8_t), 1);
}

typedef enum {
    TJEI_DC = 0,
    TJEI_AC = 1
} TJEHuffmanTableClass;

static void tjei_write_DHT(TJEState* state,
                           uint8_t const * matrix_len,
                           uint8_t const * matrix_val,
                           TJEHuffmanTableClass ht_class,
                           uint8_t id)
{
    int num_values = 0;
    int i;
    for(i = 0; i < 16; ++i) {
        num_values += matrix_len[i];
    }
    assert(num_values <= 0xffff);

    uint16_t DHT = tjei_be_word(0xffc4);
    // 2(len) + 1(Tc|th) + 16 (num lengths) + ?? (num values)
    uint16_t len = tjei_be_word(2 + 1 + 16 + (uint16_t)num_values);
    assert(id < 4);
    uint8_t tc_th = (uint8_t)((((uint8_t)ht_class) << 4) | id);

    tjei_write(state, &DHT, sizeof(uint16_t), 1);
    tjei_write(state, &len, sizeof(uint16_t), 1);
    tjei_write(state, &tc_th, sizeof(uint8_t), 1);
    tjei_write(state, matrix_len, sizeof(uint8_t), 16);
    tjei_write(state, matrix_val, sizeof(uint8_t), (size_t)num_values);
}
// ============================================================
//  Huffman deflation code.
// ============================================================

// Returns all code sizes from the BITS specification (JPEG C.3)
static uint8_t* tjei_huff_get_code_lengths(uint8_t huffsize[/*256*/], uint8_t const * bits)
{
    int k = 0;
    int i, j;
    for(i = 0; i < 16; ++i) {
        for(j = 0; j < bits[i]; ++j) {
            huffsize[k++] = (uint8_t)(i + 1);
        }
        huffsize[k] = 0;
    }
    return huffsize;
}

// Fills out the prefixes for each code.
static uint16_t* tjei_huff_get_codes(uint16_t codes[], uint8_t* huffsize, int64_t count)
{
    uint16_t code = 0;
    int k = 0;
    uint8_t sz = huffsize[0];
    for(;;) {
        do {
            assert(k < count);
            codes[k++] = code++;
        } while(huffsize[k] == sz);
        if(huffsize[k] == 0) {
            return codes;
        }
        do {
            code = (uint16_t)(code << 1);
            ++sz;
        } while(huffsize[k] != sz);
    }
}

static void tjei_huff_get_extended(uint8_t* out_ehuffsize,
                                   uint16_t* out_ehuffcode,
                                   uint8_t const * huffval,
                                   uint8_t* huffsize,
                                   uint16_t* huffcode, int64_t count)
{
    int k = 0;
    do {
        uint8_t val = huffval[k];
        out_ehuffcode[val] = huffcode[k];
        out_ehuffsize[val] = huffsize[k];
        k++;
    } while(k < count);
}
// ============================================================

// Returns:
//  out[1] : number of bits
//  out[0] : bits
TJEI_FORCE_INLINE void tjei_calculate_variable_length_int(int value, uint16_t out[2])
{
    int abs_val = value;
    if(value < 0) {
        abs_val = -abs_val;
        --value;
    }
    out[1] = 1;
    while(abs_val >>= 1) {
        ++out[1];
    }
    out[0] = (uint16_t)(value & ((1 << out[1]) - 1));
}

// Write bits to file.
TJEI_FORCE_INLINE void tjei_write_bits(TJEState* state,
                                       uint32_t* bitbuffer, uint32_t* location,
                                       uint16_t num_bits, uint16_t bits)
{
    //   v-- location
    //  [                     ]   <-- bit buffer
    // 32                     0
    //
    // This call pushes to the bitbuffer and saves the location. Data is pushed
    // from most significant to less significant.
    // When we can write a full byte, we write a byte and shift.

    // Push the stack.
    uint32_t nloc = *location + num_bits;
    *bitbuffer |= (uint32_t)(bits << (32 - nloc));
    *location = nloc;
    while(*location >= 8) {
        // Grab the most significant byte.
        uint8_t c = (uint8_t)((*bitbuffer) >> 24);
        // Write it to file.
        tjei_write(state, &c, 1, 1);
        if(c == 0xff)  {
            // Special case: tell JPEG this is not a marker.
            char z = 0;
            tjei_write(state, &z, 1, 1);
        }
        // Pop the stack.
        *bitbuffer <<= 8;
        *location -= 8;
    }
}

// DCT implementation by Thomas G. Lane.
// Obtained through NVIDIA
//  http://developer.download.nvidia.com/SDK/9.5/Samples/vidimaging_samples.html#gpgpu_dct
//
// QUOTE:
//  This implementation is based on Arai, Agui, and Nakajima's algorithm for
//  scaled DCT.  Their original paper (Trans. IEICE E-71(11):1095) is in
//  Japanese, but the algorithm is described in the Pennebaker & Mitchell
//  JPEG textbook (see REFERENCES section in file README).  The following code
//  is based directly on figure 4-8 in P&M.
//
static void tjei_fdct(FLOAT_INT32_T * data)
{
    FLOAT_INT32_T tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
    FLOAT_INT32_T tmp10, tmp11, tmp12, tmp13;
    FLOAT_INT32_T z1, z2, z3, z4, z5, z11, z13;
    FLOAT_INT32_T *dataptr;
    int ctr;

    /* Pass 1: process rows. */

    dataptr = data;
    for(ctr = 7; ctr >= 0; ctr--) {
        tmp0 = dataptr[0] + dataptr[7];
        tmp7 = dataptr[0] - dataptr[7];
        tmp1 = dataptr[1] + dataptr[6];
        tmp6 = dataptr[1] - dataptr[6];
        tmp2 = dataptr[2] + dataptr[5];
        tmp5 = dataptr[2] - dataptr[5];
        tmp3 = dataptr[3] + dataptr[4];
        tmp4 = dataptr[3] - dataptr[4];

        /* Even part */

        tmp10 = tmp0 + tmp3;    /* phase 2 */
        tmp13 = tmp0 - tmp3;
        tmp11 = tmp1 + tmp2;
        tmp12 = tmp1 - tmp2;

        dataptr[0] = tmp10 + tmp11; /* phase 3 */
        dataptr[4] = tmp10 - tmp11;

        z1 = FLOAT_2_INT32_SCALE_BACK(tmp12 + tmp13) * (FLOAT_2_INT32(0.707106781));  /* c4 */
        dataptr[2] = tmp13 + z1;    /* phase 5 */
        dataptr[6] = tmp13 - z1;

        /* Odd part */

        tmp10 = tmp4 + tmp5;    /* phase 2 */
        tmp11 = tmp5 + tmp6;
        tmp12 = tmp6 + tmp7;

        /* The rotator is modified from fig 4-8 to avoid extra negations. */
        z5 = FLOAT_2_INT32_SCALE_BACK(tmp10 - tmp12) * (FLOAT_2_INT32(0.382683433)); /* c6 */
        z2 = (FLOAT_2_INT32(0.541196100)) * FLOAT_2_INT32_SCALE_BACK(tmp10) + z5;  /* c2-c6 */
        z4 = ((FLOAT_INT32_T) FLOAT_2_INT32(1.306562965)) * FLOAT_2_INT32_SCALE_BACK(tmp12) + z5; /* c2+c6 */
        z3 = FLOAT_2_INT32_SCALE_BACK(tmp11) * ((FLOAT_INT32_T) FLOAT_2_INT32(0.707106781)); /* c4 */

        z11 = tmp7 + z3;        /* phase 5 */
        z13 = tmp7 - z3;

        dataptr[5] = z13 + z2;  /* phase 6 */
        dataptr[3] = z13 - z2;
        dataptr[1] = z11 + z4;
        dataptr[7] = z11 - z4;

        dataptr += 8;     /* advance pointer to next row */
    }

    /* Pass 2: process columns. */

    dataptr = data;
    for(ctr = 8 - 1; ctr >= 0; ctr--) {
        tmp0 = dataptr[8*0] + dataptr[8*7];
        tmp7 = dataptr[8*0] - dataptr[8*7];
        tmp1 = dataptr[8*1] + dataptr[8*6];
        tmp6 = dataptr[8*1] - dataptr[8*6];
        tmp2 = dataptr[8*2] + dataptr[8*5];
        tmp5 = dataptr[8*2] - dataptr[8*5];
        tmp3 = dataptr[8*3] + dataptr[8*4];
        tmp4 = dataptr[8*3] - dataptr[8*4];

        /* Even part */

        tmp10 = tmp0 + tmp3;    /* phase 2 */
        tmp13 = tmp0 - tmp3;
        tmp11 = tmp1 + tmp2;
        tmp12 = tmp1 - tmp2;

        dataptr[8*0] = tmp10 + tmp11; /* phase 3 */
        dataptr[8*4] = tmp10 - tmp11;

        z1 = FLOAT_2_INT32_SCALE_BACK(tmp12 + tmp13) * ((FLOAT_INT32_T) FLOAT_2_INT32(0.707106781)); /* c4 */
        dataptr[8*2] = tmp13 + z1; /* phase 5 */
        dataptr[8*6] = tmp13 - z1;

        /* Odd part */

        tmp10 = tmp4 + tmp5;    /* phase 2 */
        tmp11 = tmp5 + tmp6;
        tmp12 = tmp6 + tmp7;

        /* The rotator is modified from fig 4-8 to avoid extra negations. */
        z5 = FLOAT_2_INT32_SCALE_BACK(tmp10 - tmp12) * ((FLOAT_INT32_T) FLOAT_2_INT32(0.382683433)); /* c6 */
        z2 = ((FLOAT_INT32_T) FLOAT_2_INT32(0.541196100)) * FLOAT_2_INT32_SCALE_BACK(tmp10) + z5; /* c2-c6 */
        z4 = ((FLOAT_INT32_T) FLOAT_2_INT32(1.306562965)) * FLOAT_2_INT32_SCALE_BACK(tmp12) + z5; /* c2+c6 */
        z3 = FLOAT_2_INT32_SCALE_BACK(tmp11) * ((FLOAT_INT32_T) FLOAT_2_INT32(0.707106781)); /* c4 */

        z11 = tmp7 + z3;        /* phase 5 */
        z13 = tmp7 - z3;

        dataptr[8*5] = z13 + z2; /* phase 6 */
        dataptr[8*3] = z13 - z2;
        dataptr[8*1] = z11 + z4;
        dataptr[8*7] = z11 - z4;

        dataptr++;          /* advance pointer to next column */
    }
}
#if !TJE_USE_FAST_DCT
static FLOAT_INT32_T slow_fdct(int u, int v, FLOAT_INT32_T* data)
{
#define kPI 3.14159265f
    int x, y;
    FLOAT_INT32_T res = 0.0f;
    FLOAT_INT32_T cu = (u == 0) ? 0.70710678118654f : 1;
    FLOAT_INT32_T cv = (v == 0) ? 0.70710678118654f : 1;
    for(y = 0; y < 8; ++y) {
        for(x = 0; x < 8; ++x) {
            res += (data[y * 8 + x]) *
                   cosf(((2.0f * x + 1.0f) * u * kPI) / 16.0f) *
                   cosf(((2.0f * y + 1.0f) * v * kPI) / 16.0f);
        }
    }
    res *= 0.25f * cu * cv;
    return res;
#undef kPI
}
#endif

#define ABS(x) ((x) < 0 ? -(x) : (x))

static void tjei_encode_and_write_MCU(TJEState* state,
                                      FLOAT_INT32_T* mcu,
#if TJE_USE_FAST_DCT
                                      FLOAT_INT32_T* qt,  // Pre-processed quantization matrix.
#else
                                      uint8_t* qt,
#endif
                                      uint8_t* huff_dc_len, uint16_t* huff_dc_code, // Huffman tables
                                      uint8_t* huff_ac_len, uint16_t* huff_ac_code,
                                      int* pred,  // Previous DC coefficient
                                      uint32_t* bitbuffer,  // Bitstack.
                                      uint32_t* location)
{
    int du[64];  // Data unit in zig-zag order
    int i;
    int u, v, val, diff, last_non_zero_i;
    FLOAT_INT32_T dct_mcu[64];
    uint16_t vli[2];
    memcpy(dct_mcu, mcu, 64 * sizeof(FLOAT_INT32_T));

#if TJE_USE_FAST_DCT
    tjei_fdct(dct_mcu);
    for(i = 0; i < 64; ++i) {
        FLOAT_INT32_T fval = dct_mcu[i];
        fval *= (qt[i]);
#ifdef FLOAT_INT_MODE

#else
        fval = (fval > 0) ? floorf(fval + 0.5f) : ceilf(fval - 0.5f);
        fval = floorf(fval + FLOAT_2_INT32(1024 + 0.5f));
        fval -= FLOAT_2_INT32(1024);
#endif
        val = (int)FLOAT_2_INT32_SCALE_BACK(FLOAT_2_INT32_SCALE_BACK(fval));
        du[tjei_zig_zag[i]] = val;
    }
#else
    for(v = 0; v < 8; ++v) {
        for(u = 0; u < 8; ++u) {
            dct_mcu[v * 8 + u] = slow_fdct(u, v, mcu);
        }
    }
    for(i = 0; i < 64; ++i) {
        FLOAT_INT32_T fval = dct_mcu[i] / (qt[i]);
        val = (int)((fval > 0) ? floorf(FLOAT_2_INT32_SCALE_BACK(fval + FLOAT_2_INT32(0.5f)) : ceilf(FLOAT_2_INT32_SCALE_BACK(fval - FLOAT_2_INT32(0.5f)));
                                        du[tjei_zig_zag[i]] = val;
                                    }
#endif



    // Encode DC coefficient.
    diff = du[0] - *pred;
    *pred = du[0];
    if(diff != 0) {
        tjei_calculate_variable_length_int(diff, vli);
        // Write number of bits with Huffman coding
        tjei_write_bits(state, bitbuffer, location, huff_dc_len[vli[1]], huff_dc_code[vli[1]]);
        // Write the bits.
        tjei_write_bits(state, bitbuffer, location, vli[1], vli[0]);
    } else {
        tjei_write_bits(state, bitbuffer, location, huff_dc_len[0], huff_dc_code[0]);
    }

    // ==== Encode AC coefficients ====

    last_non_zero_i = 0;
    // Find the last non-zero element.
    for(i = 63; i > 0; --i) {
        if(du[i] != 0) {
            last_non_zero_i = i;
            break;
        }
    }

    for(i = 1; i <= last_non_zero_i; ++i) {
        // If zero, increase count. If >=15, encode (FF,00)
        int zero_count = 0;
        while(du[i] == 0) {
            ++zero_count;
            ++i;
            if(zero_count == 16) {
                // encode (ff,00) == 0xf0
                tjei_write_bits(state, bitbuffer, location, huff_ac_len[0xf0], huff_ac_code[0xf0]);
                zero_count = 0;
            }
        }
        tjei_calculate_variable_length_int(du[i], vli);

        assert(zero_count < 0x10);
        assert(vli[1] <= 10);

        uint16_t sym1 = (uint16_t)((uint16_t)zero_count << 4) | vli[1];

        assert(huff_ac_len[sym1] != 0);

        // Write symbol 1  --- (RUNLENGTH, SIZE)
        tjei_write_bits(state, bitbuffer, location, huff_ac_len[sym1], huff_ac_code[sym1]);
        // Write symbol 2  --- (AMPLITUDE)
        tjei_write_bits(state, bitbuffer, location, vli[1], vli[0]);
    }

    if(last_non_zero_i != 63) {
        // write EOB HUFF(00,00)
        tjei_write_bits(state, bitbuffer, location, huff_ac_len[0], huff_ac_code[0]);
    }
    return;
}

enum {
    TJEI_LUMA_DC,
    TJEI_LUMA_AC,
    TJEI_CHROMA_DC,
    TJEI_CHROMA_AC,
};

#if TJE_USE_FAST_DCT
struct TJEProcessedQT {
    FLOAT_INT32_T chroma[64];
    FLOAT_INT32_T luma[64];
};
#endif

// Set up huffman tables in state.
static OPTIMIZE_ATTR void tjei_huff_expand(TJEState* state)
{
    int i, k;
    assert(state);

    state->ht_bits[TJEI_LUMA_DC]   = tjei_default_ht_luma_dc_len;
    state->ht_bits[TJEI_LUMA_AC]   = tjei_default_ht_luma_ac_len;
    state->ht_bits[TJEI_CHROMA_DC] = tjei_default_ht_chroma_dc_len;
    state->ht_bits[TJEI_CHROMA_AC] = tjei_default_ht_chroma_ac_len;

    state->ht_vals[TJEI_LUMA_DC]   = tjei_default_ht_luma_dc;
    state->ht_vals[TJEI_LUMA_AC]   = tjei_default_ht_luma_ac;
    state->ht_vals[TJEI_CHROMA_DC] = tjei_default_ht_chroma_dc;
    state->ht_vals[TJEI_CHROMA_AC] = tjei_default_ht_chroma_ac;

    // How many codes in total for each of LUMA_(DC|AC) and CHROMA_(DC|AC)
    int32_t spec_tables_len[4] = { 0 };

    for(i = 0; i < 4; ++i) {
        for(k = 0; k < 16; ++k) {
            spec_tables_len[i] += state->ht_bits[i][k];
        }
    }

    // Fill out the extended tables..
    for(i = 0; i < 4; ++i) {
        assert(256 >= spec_tables_len[i]);
        tjei_huff_get_code_lengths(state->huffsize[i], state->ht_bits[i]);
        tjei_huff_get_codes(state->huffcode[i], state->huffsize[i], spec_tables_len[i]);
    }
    for(i = 0; i < 4; ++i) {
        int64_t count = spec_tables_len[i];
        tjei_huff_get_extended(state->ehuffsize[i],
                               state->ehuffcode[i],
                               state->ht_vals[i],
                               &state->huffsize[i][0],
                               &state->huffcode[i][0], count);
    }
}

static OPTIMIZE_ATTR int tjei_encode_main(TJEState* state,
        const unsigned char* src_data,
        const int width,
        const int height,
        const int src_num_components)
{
    int i, x, y, off_y, off_x;

    if(src_num_components != 3 && src_num_components != 4) {
        return 0;
    }

    if(width > 0xffff || height > 0xffff) {
        return 0;
    }

#if TJE_USE_FAST_DCT

    struct TJEProcessedQT pqt;
    // Again, taken from classic japanese implementation.
    //
    /* For float AA&N IDCT method, divisors are equal to quantization
     * coefficients scaled by scalefactor[row]*scalefactor[col], where
     *   scalefactor[0] = 1
     *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
     * We apply a further scale factor of 8.
     * What's actually stored is 1/divisor so that the inner loop can
     * use a multiplication rather than a division.
     */
    static const FLOAT_INT32_T aan_scales[] = {
        FLOAT_2_INT32(1.0f), FLOAT_2_INT32(1.387039845f), FLOAT_2_INT32(1.306562965f), FLOAT_2_INT32(1.175875602f),
        FLOAT_2_INT32(1.0f), FLOAT_2_INT32(0.785694958f), FLOAT_2_INT32(0.541196100f), FLOAT_2_INT32(0.275899379f)
    };

    // build (de)quantization tables
    for(y = 0; y < 8; y++) {
        for(x = 0; x < 8; x++) {
            FLOAT_INT32_T tmp = 0;
            int i = y * 8 + x;
            tmp = FLOAT_2_INT32(1.0f) / 8;
            tmp = FLOAT_2_INT32(tmp) / aan_scales[x];
            tmp = FLOAT_2_INT32(tmp) / aan_scales[y];
            tmp =  FLOAT_2_INT32(tmp) / INT8_2_INT32(state->qt_luma[tjei_zig_zag[i]]);
            pqt.luma[y*8+x] = tmp;
            //pqt.luma[y*8+x] = FLOAT_2_INT32(1.0f) / (8 * aan_scales[x] * aan_scales[y] * INT8_2_INT32(state->qt_luma[tjei_zig_zag[i]]));
            tmp = FLOAT_2_INT32(1.0f) / 8;
            tmp = FLOAT_2_INT32(tmp) / aan_scales[x];
            tmp = FLOAT_2_INT32(tmp) / aan_scales[y];
            tmp = FLOAT_2_INT32(tmp) / INT8_2_INT32(state->qt_chroma[tjei_zig_zag[i]]);
            pqt.chroma[y*8+x] = tmp;
        }
    }
#endif
#if 0

    {
        // Write header
        TJEJPEGHeader header;
        // JFIF header.
        header.SOI = tjei_be_word(0xffd8);  // Sequential DCT

        header.APP0 = tjei_be_word(0xffe0);

        uint16_t jfif_len = sizeof(TJEJPEGHeader) - 4 /*SOI & APP0 markers*/;
        header.jfif_len = tjei_be_word(jfif_len);
        memcpy(header.jfif_id, (void*)tjeik_jfif_id, 5);
        header.version = tjei_be_word(0x0102);
        header.units = 0x01;  // Dots-per-inch
        header.x_density = tjei_be_word(0x0060);  // 96 DPI
        header.y_density = tjei_be_word(0x0060);  // 96 DPI
        header.x_thumb = 0;
        header.y_thumb = 0;
        tjei_write(state, &header, sizeof(TJEJPEGHeader), 1);
    }
#else
//we doesn't support a standard jpeg,so the APP0 we delete it
//the device side also ignore it
    uint16_t SOI;
    SOI = tjei_be_word(0xffd8);  // Sequential DCT
    tjei_write(state, &SOI, sizeof(SOI), 1);


#endif
#if 0
//delete comment for speed
    {
        // Write comment
        TJEJPEGComment com;
        uint16_t com_len = 2 + sizeof(tjeik_com_str) - 1;
        // Comment
        com.com = tjei_be_word(0xfffe);
        com.com_len = tjei_be_word(com_len);
        memcpy(com.com_str, (void*)tjeik_com_str, sizeof(tjeik_com_str) - 1);
        tjei_write(state, &com, sizeof(TJEJPEGComment), 1);
    }
#endif
    // Write quantization tables.
    tjei_write_DQT(state, state->qt_luma, 0x00);
    tjei_write_DQT(state, state->qt_chroma, 0x01);

    {
        // Write the frame marker.
        TJEFrameHeader header;
        header.SOF = tjei_be_word(0xffc0);
        header.len = tjei_be_word(8 + 3 * 3);
        header.precision = 8;
        assert(width <= 0xffff);
        assert(height <= 0xffff);
        header.width = tjei_be_word((uint16_t)width);
        header.height = tjei_be_word((uint16_t)height);
        header.num_components = 3;
        uint8_t tables[3] = {
            0,  // Luma component gets luma table (see tjei_write_DQT call above.)
            1,  // Chroma component gets chroma table
            1,  // Chroma component gets chroma table
        };
        for(i = 0; i < 3; ++i) {
            TJEComponentSpec spec;
            spec.component_id = (uint8_t)(i + 1);  // No particular reason. Just 1, 2, 3.
            spec.sampling_factors = (uint8_t)0x11;
            spec.qt = tables[i];

            header.component_spec[i] = spec;
        }
        // Write to file.
        tjei_write(state, &header, sizeof(TJEFrameHeader), 1);
    }

    tjei_write_DHT(state, state->ht_bits[TJEI_LUMA_DC],   state->ht_vals[TJEI_LUMA_DC], TJEI_DC, 0);
    tjei_write_DHT(state, state->ht_bits[TJEI_LUMA_AC],   state->ht_vals[TJEI_LUMA_AC], TJEI_AC, 0);
    tjei_write_DHT(state, state->ht_bits[TJEI_CHROMA_DC], state->ht_vals[TJEI_CHROMA_DC], TJEI_DC, 1);
    tjei_write_DHT(state, state->ht_bits[TJEI_CHROMA_AC], state->ht_vals[TJEI_CHROMA_AC], TJEI_AC, 1);

    // Write start of scan
    {
        TJEScanHeader header;
        header.SOS = tjei_be_word(0xffda);
        header.len = tjei_be_word((uint16_t)(6 + (sizeof(TJEFrameComponentSpec) * 3)));
        header.num_components = 3;

        uint8_t tables[3] = {
            0x00,
            0x11,
            0x11,
        };
        for(i = 0; i < 3; ++i) {
            TJEFrameComponentSpec cs;
            // Must be equal to component_id from frame header above.
            cs.component_id = (uint8_t)(i + 1);
            cs.dc_ac = (uint8_t)tables[i];

            header.component_spec[i] = cs;
        }
        header.first = 0;
        header.last  = 63;
        header.ah_al = 0;
        tjei_write(state, &header, sizeof(TJEScanHeader), 1);

    }
    // Write compressed data.

    FLOAT_INT32_T du_y[64];
    FLOAT_INT32_T du_b[64];
    FLOAT_INT32_T du_r[64];

    // Set diff to 0.
    int pred_y = 0;
    int pred_b = 0;
    int pred_r = 0;

    // Bit stack
    uint32_t bitbuffer = 0;
    uint32_t location = 0;


    for(y = 0; y < height; y += 8) {
        for(x = 0; x < width; x += 8) {
            // Block loop: ====
            for(off_y = 0; off_y < 8; ++off_y) {
                for(off_x = 0; off_x < 8; ++off_x) {
                    int block_index = (off_y * 8 + off_x);

                    int src_index = (((y + off_y) * width) + (x + off_x)) * src_num_components;

                    int col = x + off_x;
                    int row = y + off_y;

                    if(row >= height) {
                        src_index -= (width * (row - height + 1)) * src_num_components;
                    }
                    if(col >= width) {
                        src_index -= (col - width + 1) * src_num_components;
                    }
                    assert(src_index < width * height * src_num_components);

                    uint8_t r = src_data[src_index + 0];
                    uint8_t g = src_data[src_index + 1];
                    uint8_t b = src_data[src_index + 2];

                    FLOAT_INT32_T luma = FLOAT_2_INT32(0.299f)   * r + FLOAT_2_INT32(0.587f)    * g + FLOAT_2_INT32(0.114f)    * b - FLOAT_2_INT32(128);
                    FLOAT_INT32_T cb   = FLOAT_2_INT32(-0.1687f) * r - FLOAT_2_INT32(0.3313f)   * g + FLOAT_2_INT32(0.5f)      * b;
                    FLOAT_INT32_T cr   = FLOAT_2_INT32(0.5f)     * r - FLOAT_2_INT32(0.4187f)   * g - FLOAT_2_INT32(0.0813f)   * b;

                    du_y[block_index] = luma;
                    du_b[block_index] = cb;
                    du_r[block_index] = cr;
                }
            }

            tjei_encode_and_write_MCU(state, du_y,
#if TJE_USE_FAST_DCT
                                      pqt.luma,
#else
                                      state->qt_luma,
#endif
                                      state->ehuffsize[TJEI_LUMA_DC], state->ehuffcode[TJEI_LUMA_DC],
                                      state->ehuffsize[TJEI_LUMA_AC], state->ehuffcode[TJEI_LUMA_AC],
                                      &pred_y, &bitbuffer, &location);
            tjei_encode_and_write_MCU(state, du_b,
#if TJE_USE_FAST_DCT
                                      pqt.chroma,
#else
                                      state->qt_chroma,
#endif
                                      state->ehuffsize[TJEI_CHROMA_DC], state->ehuffcode[TJEI_CHROMA_DC],
                                      state->ehuffsize[TJEI_CHROMA_AC], state->ehuffcode[TJEI_CHROMA_AC],
                                      &pred_b, &bitbuffer, &location);
            tjei_encode_and_write_MCU(state, du_r,
#if TJE_USE_FAST_DCT
                                      pqt.chroma,
#else
                                      state->qt_chroma,
#endif
                                      state->ehuffsize[TJEI_CHROMA_DC], state->ehuffcode[TJEI_CHROMA_DC],
                                      state->ehuffsize[TJEI_CHROMA_AC], state->ehuffcode[TJEI_CHROMA_AC],
                                      &pred_r, &bitbuffer, &location);


        }
    }

    // Finish the image.
    {
        // Flush
        if(location > 0 && location < 8) {
            tjei_write_bits(state, &bitbuffer, &location, (uint16_t)(8 - location), 0);
        }
    }
    uint16_t EOI = tjei_be_word(0xffd9);
    tjei_write(state, &EOI, sizeof(uint16_t), 1);

    if(state->output_buffer_count) {
        state->write_context.func(state->write_context.context, state->output_buffer, (int)state->output_buffer_count);
        state->output_buffer_count = 0;
    }

    return 1;
}


int tje_encode_to_ctx(void * ctx,
                      const int width,
                      const int height,
                      const int num_components,
                      const unsigned char* src_data,
                      const int quality)
{
    int res = tje_encode_to_ctx_at_quality(ctx, quality, width, height, num_components, src_data);
    return res;
}

static void tjei_stdlib_func(void* context, void* data, int size)
{
    stream_mgr_t* sg = (stream_mgr_t*)context;
    //fwrite(data, size, 1, fd);
    if(sg->dp + size < sg->max) {
        memcpy(&sg->data[sg->dp], data, size);
        sg->dp += size;
    } else
        LOGW("%s over max %d %d %d\n", __FUNCTION__, sg->dp, size, sg->max);
}

// Define public interface.
int tje_encode_to_ctx_at_quality(void * ctx,
                                 const int quality,
                                 const int width,
                                 const int height,
                                 const int num_components,
                                 const unsigned char* src_data)
{


    int result = tje_encode_with_func(tjei_stdlib_func, ctx,
                                      quality, width, height, num_components, src_data);



    return result;
}

int tje_encode_with_func(tje_write_func* func,
                         void* context,
                         const int iquality,
                         const int width,
                         const int height,
                         const int num_components,
                         const unsigned char* src_data)
{
#define MAX_JPG_QUAILITY 10
    TJEState mstate;
    TJEState *pstate ;
    uint8_t qt_factor = 1;
    int quality = iquality;
    int i;
    if(quality < 1 || quality > MAX_JPG_QUAILITY) {
        tje_log("[ERROR] -- Valid 'quality'%d values are 1 (lowest), 2,3,4,5,(highest)\n", quality);
        if(quality < 1)
            quality = 1;
        else
            quality = MAX_JPG_QUAILITY;
    }
#if 0
    pstate = xmalloc(sizeof(TJEState));
    if(!pstate) {
        LOGW("state malloc NG\n");
        return -1;
    }
#else
    pstate = &mstate;
#endif
    memset(pstate, 0, sizeof(TJEState));
    //LOGI("%s w:%d h:%d c:%d quality:%d\n",__FUNCTION__,width,height,num_components,quality);
    switch(quality) {
    case MAX_JPG_QUAILITY:
        for(i = 0; i < 64; ++i) {
            pstate->qt_luma[i]   = 1;
            pstate->qt_chroma[i] = 1;
        }
        break;
    case 9:
    case 8:
    case 7:
    case 6:
    case 5:
    case 4:
    case 3:
    case 2:

        //qt_factor = 5;
        qt_factor = quality;//less size but less quality 13.xfps
        //qt_factor = 2;//13.xfps
        //qt_factor = 4;//13.xfps
        // don't break. fall through.
    case 1:
        for(i = 0; i < 64; ++i) {
            pstate->qt_luma[i]   = tjei_default_qt_luma_from_spec[i] / qt_factor;
            if(pstate->qt_luma[i] == 0) {
                pstate->qt_luma[i] = 1;
            }
            pstate->qt_chroma[i] = tjei_default_qt_chroma_from_paper[i] / qt_factor;
            if(pstate->qt_chroma[i] == 0) {
                pstate->qt_chroma[i] = 1;
            }
        }
        break;
    default:
        assert(!"invalid code path");
        break;
    }

    TJEWriteContext wc = { 0 };

    wc.context = context;
    wc.func = func;

    pstate->write_context = wc;


    tjei_huff_expand(pstate);

    int result = tjei_encode_main(pstate, src_data, width, height, num_components);

    //xfree(pstate);
    return result;
}
// ============================================================
#endif // TJE_IMPLEMENTATION
// ============================================================
//
#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic pop
#endif



